info lifted from http://johnson.tmfc.net/dos/shsucdx.html
SHSUCDX - A CD-ROM driver replacement of MSCDEX coded by John H. McCoy
(up to version 1.4) and then improved by Jason Hood until version
3.02.
SHSUCDX V3.02 was released on 2005-05-05. Some users (such as I)
downloaded it and tried to replace the old version, thinking it SHOULD
be better. Some developers tried to change the source code to suit
their needs (usually deleting text to save a few bytes), but this is
where their problems began...
On 2005-05-15, Mr. Jack Ellis e-mailed me and suggested the latest
version might have a potential problem, and he considered it was NOT
perfectly reliable. On 2005-05-17 another developer, Robert Riebisch
(BTTR Software), also reported to the FreeDOS mailing list that he had
failed to compile it without errors.
[..]
Jack Ellis ("I need something that WORKS!") decided to work around the
NASM error and clean up the SHSUCDX V3.00 source. He did it in the
afternoon of 2005-05-22, and made some more changes in the next few
days; thus Jack's "SHSUCDX V3.00A" was born. Since this version worked
fine, he later decided to clean up V3.02 also, so other developers
could make changes and improvements to it. Thanks to his HARD WORK,
SHSUCDX V3.02A and its successors became available.
Thanks to Jason Hood for providing a link to this page, regarding this
version as an "alternative" to his work.
Though Jack tried his best to avoid bugs, thousands of different
machines out there may cause unpredictable problems.